New microcoil enhances NMR sensitivity.To a biological molecule, a nanoliter might as well be an ocean. But to molecular biologists, one-billionth of a liter is a volume so restricted that accurate chemical analysis of it can become an exercise in frustration. To overcome such difficulties, Dean L. Olson and Jonathan V. Sweedler, chemists at the University of Illinois at Urbana-Champaign Early years: 1867-1880 The Morrill Act of 1862 granted each state in the United States a portion of land on which to establish a major public state university, one which could teach agriculture, mechanic arts, and military training, "without excluding other scientific and their colleagues have fabricated fab·ri·cate tr.v. fab·ri·cat·ed, fab·ri·cat·ing, fab·ri·cates 1. To make; create. 2. To construct by combining or assembling diverse, typically standardized parts: a microcoil small enough to permit accurate molecular analysis of tiny samples with nuclear magnetic resonance nuclear magnetic resonance: see magnetic resonance. nuclear magnetic resonance (NMR) Selective absorption of very high-frequency radio waves by certain atomic nuclei subjected to a strong stationary magnetic field. (NMR NMR: see magnetic resonance. ). "We think that the biggest impact of the NMR microcoils will be to enhance separation techniques," says Sweedler. Current NMR systems cannot be used to analyze samples produced during separation if the samples are smaller than about 50 microliters, Sweedler says. Using the diminutive NMR coils in conjunction with standard separation techniques adapted to small volumes-such as capillary electrophoresis Capillary electrophoresis (CE), also known as capillary zone electrophoresis (CZE), can be used to separate ionic species by their charge and frictional forces. In traditional electrophoresis, electrically charged analytes move in a conductive liquid medium under the or liquid chromatography-chemists can assay nanosamples with 100 times the sensitivity now possible with conventional NMR methods alone, Olson and Sweedler report in the Dec. 22, 1995 Science. "The microcoils let us work with 5-nanoliter samples, which are 10,000 times smaller than samples currently used," Sweedler says. "You can measure some things that couldn't be measured before." Sweedler predicts that the microcoil will greatly improve analysis of biological materials. "If you're isolating a peptide or trace component of a cell," he says, "you often don't have enough material to use conventional NMR." "This is a very important contribution," says Charles S. Johnson ''This article is about the sociologist and university president. For the American football player, please see Charles S. Johnson (football). Charles Spurgeon Johnson Jr., an analytical chemist at the University of North Carolina at Chapel Hill The University of North Carolina at Chapel Hill is a public, coeducational, research university located in Chapel Hill, North Carolina, United States. Also known as The University of North Carolina, Carolina, North Carolina, or simply UNC . "NMR is an exceptional technique when it comes to chemical selectivity. But its sensitivity is poor in small samples, which has limited its use." The magnets for an NMR system currently cost more than any other component, Sweedler adds. "With smaller coils, you can scale down the size of the magnets. That could cut the cost from more than $100,000 per magnet to less than $10,000. In the long run, that might make possible inexpensive bench-top NMR machines." The size of the NMR microcoil in relation to a penny. |
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